A Brief Look at Homelessness - 822 Words

Investigate a Social Issue Draft 1. Specific Hypothesis Why are people homeless? I think people are homeless because, homelessness and poverty are linked. Poor people are sometimes unable to pay for housing, food, childcare, health care, and education. At times some difficult choices must be made when limited resources cover only some of these necessities. Paying rent takes up a lot of ones paycheck so would be the first to go if money was tight. Two factors help account for increasing poverty: employment and the declining value and availability of public assistance. A lack of affordable housing and the limited housing assistance programs have contributed to the current housing crisis and to homelessness. But what all of this comes down to homelessness is defined as: The condition of a person or persons living without a regular dwelling... 2. Applicable Sociological Concepts A. Conflict Theory Most people become homeless due to circumstances that have overwhelmed them combined with hardly any family support structure. Conflict-theorists would most likely not consider homelessness, in itself, to be a problem whatsoever. A conflict theorist would claim that the reason the homeless problem persists is not because of a homeless individuals supposed inability to advance oneself. Rather, the conflict theorist would say that the cause of homelessness stems from those who cannot find a place to work or a physical address to call home. Therefore, when the state deniesShow MoreRelatedHomelessness : The Current Social Welfare Issue1339 Words   |  6 PagesSocial Welfare Issue: Homelessness Written by: Laura Westra The current social welfare issue that I chose to explore is homelessness within Canada. First, this essay will give a brief description of homelessness. Secondly, it will describe how homelessness relates to some concepts and theories that we learned in this course Introduction to Social Welfare, it will also look at what may have happened to people facing homelessness one hundred years ago, next we will explore a possible solution to thisRead MoreHomelessness Is A Problem Of Homelessness1658 Words   |  7 PagesHomelessness in Society Imagine you are homeless and have no shelter, or nowhere to go. You walk through storms in the same clothes you had on a week ago. You look around for help, but there is none. What would you do? Or imagine you are one of the forgotten ones, whom people call dirty, and disgusting. Suddenly you hear footsteps, with hope filled inside you, and then a sudden sadness strikes you as the 1378th careless person walks by you and doesn t notice you. All you want is somewhere to sleepRead MoreDealing with Homelessness in Australia Essay examples1400 Words   |  6 PagesHomelessness is all our responsibility. Waking every morning in a warm bed in a secure house for some Australians is only a dream. Every day more and more people are becoming or are at risk of becoming homeless as the global economy crumbles away and monetary resources become harder to find. What is homelessness: the Australian Government Department of Health (2005) defines homelessness as a person who is without a conventional home. Homeless Australians have become disconnected from family and friendRead MoreThe City Of Vancouver Is World Renowned For Being A Beautiful1740 Words   |  7 PagesVancouver has a large a mount of poverty and homelessness. The DTES has high rates of â€Å"drug use, poverty, crime, infectious disease, and mental illness† (Linden, Mar, Werker, Jang, Krausz, 2013, p. 559). There is a large amount of socially neglected and undesirable people living in the marginalized area. The following paper explores and focuses on the social impacts (internal and external) of the inhabitants of the DTES within the city of Vancouver, with a brief overview of the economic impacts. The DTESRead MoreThe Lack Of Mental Health Treatment1528 Words   |  7 Pagesshare when discussing someone’s experience with the lack of mental health treatment. Throughout my research a couple stories jumped out at me and one of them was about a young man named Lorenzo from California suffering from schizophrenia. This was a brief story that was shared and his turn around to recovery because of the help provided. Lorenzo’s Story According to his mother, Lorenzo was a typical boy growing up in California. He enjoyed helping around the house and playing with his friends. But aroundRead MoreEmpathy Vs. Compassion Essay1293 Words   |  6 Pages13). In other words, true compassion can only be learned when one is faced with it every day of ones life and that once it becomes â€Å"familiar†, only then it can become identifiable and conjure empathy. Ascher’s â€Å"On Compassion† offer readers a brief encounter with New York City’s citizens as they confront the less fortunate members of society- the homeless. She describes a young mother walking down the street with her baby in a stroller who becomes agitated upon seeing a homeless man walkingRead More Homeless - The Ignored Community Essay example1497 Words   |  6 Pagessign. Hes just looking for easy money, commented one friend. While this is a possible reason, a more complicated one came to my mind. Perhaps this was a homeless man who had used up his time at the local shelter. Many people do not think homelessness is a problem, but the homeless people, mostly unseen, exist in ever-increasing numbers. The homeless are like a bowl of popcorn; an uncooked kernel of popcorn goes unnoticed until you bite down on it. Just like the homeless are notRead MoreHomelessness And The Homeless Community1855 Words   |  8 Pages Some people saunter by these downtrodden individuals unconcerned, while others give them sympathetic looks and drop a few coins in their cups. We are aware of homelessness, almost too aware and yet we go on with our lives without further regard. Homelessness has become such an epidemic in the United States that it is normal and practically expected to be seen in our urban streets. Homelessness is defined by the Merriam-Webster dictionary as, â€Å"Having no home or permanent residence.† While that isRead MoreHomelessness Paper2330 Words   |  10 PagesHomelessness is defined as â€Å"An Individual who lacks a fixed regular and adequate nighttime residence†, (Burt, 1989, p.17). Have you ever stopped to wonder how many people are Homeless? Who are most at risk to fall into this situation? I highly doubt it. While most people really do not care and ignore homeless people, others look at them as motivation, people whom they do not want to become. Another question that comes to mind is, how do homeless people survive and what are their legal rights.Read MoreThe Goal Of Foster Care1182 Words   |  5 PagesIntervention The goal of foster care is reunification, which is the overall goal of having children placed in foster care for a brief period until the legal guardian is able to gain back custody of the child. The goal of the agency is to identify the gaps when reuniting children back with family members, and stating resolutions to the problem areas. According to Wulcyzn 2004, â€Å"Although many children who are reunified exit the system within a relatively short period of time, reunification often do

China s One Child Policy - 1631 Words

The One Child Policy China has had the new population control for almost 36 years, composed by the one-child policy and prohibited excess reproduction. The birth control plan has received praise on reducing the population, but also received criticism over the late 20th century. In 1979, couples were forced to pledge not to give second birth or bear any more children (Feng, 2014). From 1979 to 2015, while the population growth rate has reduced substantially, this implementation has been tremendously restructured how Chinese families value family structure, child preferences, marriage, parenting, living arrangements, and eldercare. This one child policy has transformed into a problematic system for the Chinese family to maintain their traditional value, and also introduced new problems to the family. Family Size and Structure As an immediate outcome of the one child policy effective on 1979, the fertility rate has cut more than 50% of its total fertility rate in 1970, six births, to 2.3 births by 1980 (Coale Chen, 1987). A survey data of 1,293 families in Hubei Province has shown 80 percent of their family size were three, and out of all the three-member families, they were all only-child families (Feng, 2014). This new family structure was very different from the baby boomers generation (the parent), and both sides of the parent have introduced their families into a â€Å"four-two-one† structure, which is four grandparents, two parents, and a child. Before the implementation ofShow MoreRelatedChina s One Child Policy1000 Words   |  4 PagesChina’s One Child Policy. This is something that I am against. I do not think you should limit a family to one child. There are many problems with this policy that I do not think were thought about when the policy was created. I have not found many go od things about this policy. The only positive thing I have found about this policy is that it creates many chances for adoption. But most of these children who are up for adoption do not get adopted. So I do not support China’s one-child policy. One reasonRead MoreChina s One Child Policy1745 Words   |  7 PagesChina’s One Child policy is a policy that the Chinese government introduced in 1979 to try and solve the problem of overpopulation. The Policy’s main purpose was to make sure that China could support its large population with facilities such as healthcare, education, housing, good jobs and most importantly, food. The aim was to reduce poverty and to improve overall quality of life for the people. China’s one-child policy has led to unintended and negative consequences, such as a diminishing laborRead MoreChina s One Child Policy1227 Words   |  5 PagesThe one child policy in the Peoples Republic of China has recently been lifted to allowed families to freely have two children rather than one. This policy, introduced to China in the late 1970’s, was due to a massive baby boom which had taken place in the 1960’s. In the early to late 1950’s the Chinese government had encou raged its citizens to produce children at a rapid rate in the hope of building a larger work force (Managing Population Change Case Study: China). In order to counteract this boomRead MoreChina s One Child Policy1925 Words   |  8 Pagespeople. It is the most populous country in the world and it is only increasing. The Chinese government has spent more than 40 years trying to slow their population growth. They have done so through their controversial one child policy. There is no denying that China’s one child policy changed the lives of Chinese citizens when it the Chinese Communist Party [CCP] in 1979 as a way of controlling population. Under Mao, the government encouraged families to have as many children as possible, believingRead MoreChina s One Child Policy964 Words   |  4 PagesThus, by 1975, the Chinese government had reversed their policy on population growth (Clarke), adopting the slogan â€Å"Later, Longer, Fewer.† This campaign urged couples to have tw o to three children and to begin reproducing at a later age, as well as promoting improved sanitation and healthcare to as to increase life expectancy (â€Å"5 Things to Know About China’s 1-Child Policy†). In 1979, the Chinese government introduced the One-Child Policy, which consisted of a set of regulations governing the approvedRead MoreRepercussions Of China s One Child Policy883 Words   |  4 PagesChina’s One Child Policy â€Å"China Will Have another Major Demographic Problem,† is an article on About.com written by Matt Rosernberg. It explains the great imbalance between man and women due to China’s One Child Policy, and how this situation will disturb the stability and development of China because the high numbers of bachelors tend to damage community by doing crimes and violence. The policy says that a couple could only have a child. This was created as a temporary solution since China was overpopulatedRead MoreChildren Of The Dragon : China s One Child Policy1298 Words   |  6 PagesChildren of the Dragon: China’s One-Child Policy The earth’s growing population is a global concern. Both developed and third-world countries, are experiencing shortages of food, water and access to adequate healthcare. Although the poorest are hardest hit, even powerful countries like the United States and Great Brittan have been affected. Recent shortages of medication and fuel are contributing to speculation and concern. Governments the world over are turning to alternative energy and sustainableRead MoreUnintended Consequences Of China s One Child Policy1907 Words   |  8 Pagescontradicts the one-child policy implemented in China. The one-child policy was a program designed to restrict Chinese families to only one child, with severe consequences lined up for those who disobeyed. It was met with harsh opposition, from Chinese citizens as well as from other countries. The policy succeeded in creating smaller families, but it unleashed a slew of unintended consequences, including a higher crime rate and an increase in the elderly population, who only have one child to supportRead MoreChina s One Child Policy : Destructive Or Constructive?2001 Words   |  9 PagesChina’s One-Child Policy: Destructive or Constructive? Classical Argument Essay China’s one-child policy has created a wide range of debates as to whether it is helpful or detrimental to the country due to the conditions it holds. In 1978, China discussed a law stating married couples could only have one child within their lifetime. This policy was eventually applied a couple years later, in 1980, after they discussed the various terms of the policy. After several years of action, China added flexibilityRead MoreChina And Indi Driving Forces Of Overpopulation712 Words   |  3 PagesEmre Can AydÄ ±n Writing Assignment 104A 03/15/2015 China and India: Driving Forces of Overpopulation According to BBC, India s population reached nearly 1.21bn (India census: population goes up to 1.21bn). China is also has the population of 1.36bn according to Chinese Government (China Statistical Yearbook-2014). That s almost the half of the Earth s population. There are negative outcomes of this situation like poverty, depletion of resources and disturbed cultural structures. Actually

The Curriculum-What Is To Be Taught Free Essays

In making instructional decisions the instructors must consider the following factors which include what is to be taught, how it should be taught and the student’s needs. John Dewey was very instrumental in bringing the concept of decision making theory into the educational field. He further presented it in a process that was known as the reflective thinking which involved four phases which are; the problem phase, the criteria phase, the solution phase, and finally the implementation phase. We will write a custom essay sample on The Curriculum-What Is To Be Taught? or any similar topic only for you Order Now (Auerbach, 2003) The Curriculum-What Is To Be Taught? Is the curriculum guaranteed such that is it taught in a way that it was intended? Is the curriculum viable such that it can be adequately addressed in the time available? Is the curriculum rigorous such that it ensures that all the students’ areas have been adequately challenged? Is the curriculum relevant such that it fosters smooth transitions between the elementary schools, the middle schools, the high schools, the post secondary schools and later to the world of work? Are the decisions about the curriculum uniformly applied to all the students?   Is there a lot of emphasis on mastering predetermined and common curricular objectives? Is the curriculum used standard for all the students?   Is the curriculum relevant to the students?   Does the curriculum have an outline that allows for the differences in the students backgrounds, abilities interests and prior knowledge and for the differences in the expectations from the community? How to cite The Curriculum-What Is To Be Taught?, Papers

Is The World as Bad as We Think free essay sample

If you go to the gym, or turn your radio on, or pick up the daily newspaper, or visit the grocery store, or turn the news on TV, what do you hear? A man complaining about his weight loss. A song about the end times on the radio. Another small business failed in the paper. A clerk working at the grocery mart talking about a hurricane soon to destroy the coast of North Carolina. Bill Fraisher discussing that Japan may never recover from the tsunami. Is this world that we live in today really this bad? Is it really becoming worse every day? I think the world is good, and it gets better everyday. We have better transportation. We have more leisure time than ever. We can visit our grocery store and buy food from all over the world. We have freedom of thinking that gives us the passion to build what we want, write what we want, see what we want, and think what we want. We will write a custom essay sample on Is The World as Bad as We Think? or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page I like the world we live in today. No matter what world we live in, past, present or future, that world depends on the way we think. The only way any world is made better is for her people to think positively and to appreciate what we have. I would recommend that the guy at the gym be happy that he has a gym membership. I recommend the end times band should appreciate that the world hasnt ended yet. I recommend that writer of the failed business article should write on how to not keep your own business from not failing. I recommend that the clerk thinks about what she could do for the victims of the hurricane in North Carolina. A person who only thinks about herse himself will not be satisfied in the world that he lives in. A person that thinks his world and everything around him is gloom and doom, can change it. I truly think what we can do is lend a helping hand, give a dollar to Red-Cross, open a door for the old lady, or buy an apple for the homeless man. If everyone in the world did one good deed for someone else, and experienced the appreciation of that good deed, their world would be a good one.

The Story of Noah free essay sample

A discussion of Timothy Findleys Not Wanted on the Voyage, a retelling of the biblical story of Noah. The following paper examines the story of Noah or rather the story of the destruction of the world that exists at the beginning of time and then its recreation after a flood. This paper explores the fascinating aspects of Findleys book that reminds us that the story of Noah is really a story about how God admits to making a mistake and having to start again with a fresh slate. The story of Noah and the flood is a fascinating one, not in the least because it allows us to draw connections between Christianity and a number of other religions. While it is certainly not universally true that all creation stories include tales of great floods, such stories are so common across the breadth of the worlds cultures and the length of history that they seem to constitute more the rule than the exception. We will write a custom essay sample on The Story of Noah or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Timothy Findleys Not Wanted on the Voyage is thus more than simply a retelling of a biblical story; it is also a retelling of an essentially and nearly pan-human story, and we should read it in this context.

JB HI FI Analysis Essays

JB HI FI Analysis Essays JB HI FI Analysis Essay JB HI FI Analysis Essay B HI-If is a well-known and successful cooperation that majors in house hold appliances, technological goods and the stock shares, the JOB HI-If Cooperation was established in 1974 by Mr.. John Barbour B), trading from a single store in East Killer, Victoria. Since then JOB HI-If was sold independently in 1983 from there on the business grew. In 1999 another nine stores were opened nationwide. Shortly thereafter In July 2000 JOB Hi-If was purchased yet again by private equity bankers and senior managements in the opinion of expanding the current growth. In October 2003, JOB HI-If was floated on the Australian Stock Exchange. By July 2004, JOB purchased the Queensland Clive Anthony chain of stores which specialist in consumer electronics, white goods, cooking appliances and air-conditioning systems this advance forward gave the JOB HI-If cooperation the reputation they have today. JOB stores offer the worlds leading brands of Hi-If, Speakers, Televisions, DVDs, Vics, Cameras, Car Sound, Home Theatre, Computers and Portable Audio and continue to stock an exclusive range of specialist Hi-If products. JOB Hi-If also offers the largest range of video games, recorded music, DVD music and DVD movies with ever 50,000 CDC and most major studio DVD releases, all at cheap prices! Customers are able to buy online from their huge range of CDC, DVDs, and games This report will look at the accounting period of 2011/2010 and compare them with previous years of 2009/2008. We will also be looking at the same accounting period for the Harvey Norman group and compare the results with JOB HI-Fl. The Board responsibilities include the corporate governance of the Company, overseeing the business and affairs of the Company, communicating with the Companys shareholders and the immunity, evaluating the performance of executives, ensuring that appropriate procedures are in place so that Company is conducted in an honest, open and ethical manner and the establishment of a formal and transparent procedure for the selection, appointment and review of Board directors. The Chief Executive Officer, who is accountable to the Board, is responsible for managing, directing and promoting the profitable operation and development of JOB Hi-If.

Describe the everyday life Essay Example | Topics and Well Written Essays - 250 words

Describe the everyday life - Essay Example Unconscious emotions may be fully understood in the context of mood swings. Most people may wake up in a bad mood or good mood, but they may find it hard to articulate and pinpoint the root source of the happiness (Wyer, 2014, p. 38). Human beings pass judgment on other people through thin-slicing. Thin slicing is a phenomenon by which human beings tend to judge others with limited information such as the first impression due to previous experiences of a similar nature. Henri Lefebvre’s works focus on describing and bringing a terse meaning of everyday life through introducing concepts such as â€Å"social space† and the â€Å"right to the city.† In his book, â€Å"Le Droit à   la ville† he discusses dwells on the concepts, where he proposes reforms that will improve everyday life for the betterment of the society (Lefebvre, 2002, p 19). Conclusively, Lefebvre’s theory insinuates that through the betterment of cities and urban centers, everyday life will improve and inflicting happiness among people. However, some of these unconscious actions maybe as a result of deliberate learning and thereafter become automotive due to repetitive undertakings by human beings. Most people show more care in the initial phase after a driving course. However, a person may be more at ease after some time and may subconsciously engage in other activities while driving (Bargh, 2013, p.

Business Essay Example | Topics and Well Written Essays - 750 words - 1

Business - Essay Example 136). A business organization’s environment may not be susceptible to change, and this could continue for several years. Such organizations are characterized by stability and predictability. However, there could be business organizations that are significantly influenced by the changes that transpire in their environment. In such instances, the business organization could undergo intricate, frequent, and rapid changes (Dyer & Ross, 2008, p. 137). Business should adopt changes according to its environmental factors. A dynamic business environment is one that adopts changes quickly according to the surrounding issues; such as government policies, availability of employees and competition from other business organizations in the field. The more important business functions are facilities and security, finance, human resources, information technology, legal requirements and compliance with the same, manufacturing, marketing and sales, operations, research and development, and inve ntory, order fulfillment, shipping and receiving (Snedaker, 2007, pp. 225 – 226). Any contingency plan has to take these functions into consideration. Thus, the incident response (IR) plan concentrates on immediate response. In case the attack increases in ferocity, the disaster recovery (DR) plan or business continuity (BC) plan has to be undertaken. The DR plan focuses on restoring systems at the original location, subsequent to the occurrence of the disaster. On the other hand, the BC plan is implemented along with the DR plan, in instances where the damage is substantial and ongoing. In other words, this combined intervention is reserved for situations, in which something more than simple restoration of information and resources related to information are required. The purpose of the BC plan is to establish the critical business functions at a different location (Whitman & Mattord, 2011, p. 212). Appropriate planning will save an organization from critical situations. Pla ns such as disaster recovery and business continuity will help in restoring the system to normalcy, in an efficient manner. . Human Systems Integration is a system that brings about the integration of human capabilities, their limitations, and preferences into an engineering system. It brings business and engineering cultures closer to a human centric mechanism, which produces significant performance and cost advantages. These benefits would not have been possible, but for this initiative. All the same, Human Systems Integration demands a cultural change that should commence with the organizational leadership (Booher, 2003, p. xv). Human systems integration would benefit the organization by enhancing the capacity of the workers, while simultaneously reducing costs. Business organizations should be socially responsible, and should conform to the extant social standards, values, and ethics. In the 2000s, several financial scandals surfaced in the US, which served to create disgust and distrust in the public towards the corporate sector. In order to rectify this untenable and unwelcome situation, the US Congress passed the Sarbanes – Oxley Act (Ferrell, Hirt, & Ferrell, 2008, p. 39). This Act made securities fraud a crime and significantly enhanced the penalties for corporate fraud. The managers of a company have to necessarily comply with the existing laws and regulations. Companies face difficulties with the law, when they indulge in activities

HR contributes at SYSCO Case Study Example | Topics and Well Written Essays - 250 words

HR contributes at SYSCO - Case Study Example Administrative roles include recruitment and selection focus and supervisory training that deals largely with policy and procedures. Communications of pre-existing OSHA regulations and compliances may have impacted safety, such as developing a marketed campaign to develop a corporate culture of safety through vision or mission discussions company-wide. Training for better job competency could have also impacted safety positively. Employee turnover might have been improved by creating softer HR policies that included training for autonomous work, creating a unified organizational culture, or flexible job strategies to provide motivation. Programs such as this usually build more dedication in employees by appealing to their psycho-social needs. Increases in customer satisfaction could be attributed to the benefits of the workplace climate survey to show employees that they are valuable members of the organization to appeal to their need for shared business decision-making. This makes for more productive outputs by employees by decentralizing

Digital Signal Processing (DSP) and CDMA Advantages

Digital Signal Processing (DSP) and CDMA Advantages INTRODUCTION ANALOG AND DIGITAL SIGNALS The signal is initially generated is in the form of an analog electrical voltage or current, produced for example by a microphone or some other type of transducer. The output from the readout system of a CD (compact disc) player, the data is already in digital form. An analog signal must be converted into digital form before DSP techniques can be applied. An analog electrical voltage signal, for example, can be digitized using an electronic circuit called an analog-to-digital converter or ADC. This generates a digital output as a stream of binary numbers whose values represent the electrical voltage input to the device at each sampling instant. Digital signal processing (DSP)-digital representation of signals and the use of digital processors to analyze, modify, or extract information from signals. Many signals in DSP are derived from analogue signals which have been sampled at regular intervals and converted into digital form. The key advantages of DSP over analogue processing are Guaranteed accuracy (determined by the number of bits used) Perfect reproducibility No drift in performance due to temperature or age Takes advantage of advances in semiconductor technology Greater flexibility (can be reprogrammed without modifying hardware) Superior performance (linear phase response possible, and filtering algorithms can be made adaptive) Sometimes information may already be in digital form. There are however (still) some disadvantages Speed and cost (DSP design and hardware may be expensive, especially with high bandwidth signals) Finite word length problems (limited number of bits may cause degradation). Application areas of DSP are considerable: Image processing (pattern recognition, robotic vision, image enhancement, facsimile, satellite weather map, animation) Instrumentation and control (spectrum analysis, position and rate control, noise reduction, data compression) Speech and audio (speech recognition, speech synthesis, text to speech, digital audio, equalisation) Military (secure communication, radar processing, sonar processing, missile guidance) Telecommunications (echo cancellation, adaptive equalisation, spread spectrum, video conferencing, data communication) Biomedical (patient monitoring, scanners, EEG brain mappers, ECG analysis, X-ray storage and enhancement). INTRODUCTION TO CDMA Code Division Multiple Access (CDMA) is a radically new concept in wireless communications. It has gained widespread international acceptance by cellular radio system operators as an upgrade that will dramatically increase both their system capacity and the service quality. It has likewise been chosen for deployment by the majority of the winners of the United States Personal Communications System spectrum auctions. It may seem, however, mysterious for those who arent familiar with it. CDMA is a form of spread-spectrum, a family of digital communication techniques that have been used in military applications for many years. The core principle of spread spectrum is the use of noise-like carrier waves, and, as the name implies, bandwidths much wider than that required for simple point-to-point communication at the same data rate. Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called low probability of intercept (LPI). It has a history that goes back to the early days of World War II. The use of CDMA for civilian mobile radio applications is novel. It was proposed theoretically in the late 1940s, but the practical application in the civilian marketplace did not take place until 40 years later. Commercial applications became possible because of two evolutionary developments. One was the availability of very low cost, high density digital integrated circuits, which reduce the size, weight, and cost of the subscriber stations to an acceptably low level. The other was the realization that optimal multiple access communication requires that all user stations regulate their transmitter powers to the lowest that will achieve adequate signal quality. CDMA changes the nature of the subscriber station from a predominately analog device to a predominately digital device. Old-fashioned radio receivers separate stations or channels by filtering in the frequency domain. CDMA receivers do not eliminate analog processing entirely, but they separate communication channels by means of a pseudorandom modulation that is applied and removed in the digital domain, not on the basis of frequency. Multiple users occupy the same frequency band. This universal frequency reuse is not fortuitous. On the contrary, it is crucial to the very high spectral efficiency that is the hallmark of CDMA. Other discussions in these pages show why this is true. CDMA is altering the face of cellular and PCS communication by: Dramatically improving the telephone traffic capacity Dramatically improving the voice quality and eliminating the audible effects of multipath fading Reducing the incidence of dropped calls due to handoff failures Providing reliable transport mechanism for data communications, such as facsimile and internet traffic Reducing the number of sites needed to support any given amount of traffic Simplifying site selection Reducing deployment and operating costs because fewer cell sites are needed Reducing average transmitted power Reducing interference to other electronic devices Reducing potential health risks Commercially introduced in 1995, CDMA quickly became one of the worlds fastest growing wireless technologies. In 1999, the International Telecommunications Union selected CDMA as the industry standard for new third-generation (3G) wireless systems. Many leading wireless carriers are now building or upgrading to 3G CDMA networks in order to provide more capacity for voice traffic, along with high-speed data capabilities. DS_CDMA Multiple access systems based on DS CDMA have achieved increasing significance for mobile communications applications. A promising concept is based on DS_CDMA applying MRC at the receiver. MRC takes advantage of the channel diversity to combat the multipath fading. However the capacity of a DS_CDMA system is limited by both multi-user interference and inter symbol interference ISI in high data rate applications. OFDM is applied to combat the frequency selectivity of the channel using a simple one tap equalizer Further more OFDM prevents the ISI and inter carrier interference ICI by inserting a guard interval between adjacent OFDM symbols OFDM is typically used for audio TV and HDTV transmission over terrestrial channels and achieves high spectral efficiency. The CMDA Technology overview FDMA In Frequency Division Multiple Access, the frequency band is divided in slots. Each user gets one frequency slot assigned that is used at will. It could be compared to AM or FM broadcasting radio where each station has a frequency assigned. FDMA demands good filtering. TDMA In Time Division Multiple Access, the frequency band is not partitioned but users are allowed to use it only in predefined intervals of time, one at a time. Thus, TDMA demands synchronization among the users. CDMA CDMA, for Code Division Multiple Access, is different from its traditional ways in which it does not allocate frequency or time in user slots but gives the right to use both to all users simultaneously. To do this, it uses a technique known as Spread Spectrum . In effect, each user is assigned a code,which spreads its signal bandwidth in such a way that only the same code can recover it at the receiver end. This method has the property that the unwanted signals with different codes get spread even more by the process, making them like noise to the receiver . Spread Spectrum Spread Spectrum is a mean of transmission where the data occupies a larger bandwidth than necessary. Bandwidth spreading is accomplished before the transmission through the use of a code, which is independent of the transmitted data. The same code is used to demodulate the data at the receiving end. The following figure illustrate the spreading done on the data signal x(t) by the spreading signal c(t) resulting in the message signal to be transmitted, m(t). Originally for military use to avoid jamming (interference created on purpose to make a communication channel unusable), spread spectrum modulation is now used in personal communication systems for its superior performance in an interference dominated environment . Definition of Spread Spectrum: A transmission technique in which a pseudo-noise code, independent of the information data, is employed as a modulation waveform to â€Å"spread† the signal energy over a bandwidth much greater than the signal information bandwidth. At the receiver the signal is â€Å"despread† using a synchronized replica of the pseudo-noise code. Basic Principle of Spread Spectrum System: The Principal types of Spread Spectrum are Direct Sequence (DS), and Frequency Hopping (FH). An over view of these systems is hereby given: Pseudo shift of the phase pseudo shift of the frequency Coherent demodulation noncoherent Direct Sequence Spread Spectrum (DSSS) A pseudo-noise sequence pnt generated at the modulator, is used in conjunction with an M-ary PSK modulation to shift the phase of the PSK signal pseudo randomly, at the chipping rate Rc (=1/Tc) a rate that is integer multiple of the symbol rate Rs (=1/Ts). The transmitted bandwidth is determined by the chip rate and by the base band filtering. The implementation limits the maximum chip rate Rc (clock rate) and thus the maximum spreading. The PSK modulation scheme requires a coherent demodulation. PN code length that is much longer than a data symbol, so that a different chip pattern is associated with each symbol. Frequency Hopping Spread Spectrum A Pseudo-noise sequence pnt generated at the modulator is used in conjuction with an M-ary FSK modulation to shift the carrier frequency of the FSK signal pseudurandomly, at the hopping rate Rh. The transmitted signal occupies a number of frequencies in time, each for a period of time Th (= 1/Rh), referred as dwell time. FHSS divides the available bandwidth into N channels and hops between these channels according to the PN sequence. At each frequency hop time the PN generator feeds the frequency synthesizer a frequency word FW (a sequence of n chips) which dictates one of 2n frequency position fhl . Transmitter and receiver follows the same frequency hop pattern. The transmitted bandwidth is determined by the lowest and highest hop position by the bandwidth per hop position (à ¢Ã‹â€ Ã¢â‚¬  fch). For a given hop, instantaneous occupied bandwidth is the conventional M-FSK, which is typically much smaller than Wss. So the FHSS signal is a narrowband signal, all transmission power is concentrated on one channel. Averaged over many hops, the FH/M-FSK spectrum occupies the entire spread spectrum bandwidth. Because the bandwidth of an FHSS system only depends on the tuning range, it can be hopped over a much wider bandwidth than an DSSS system. Since the hops generally result in phase discontinuity (depending on the particular implementation) a noncoherent demodulation is done at receiver. With slow hopping there are multiple data symbol per hop and with fast hopping there are multiple hops per data symbol. 3.3 Basic principle of Direct Sequence Spread Spectrum For BPSK modulation the building blocks of a DSSS system are: Input: Binary data dt with symbol rate Rs = 1/Ts (=bitrate Rb for BPSK) Pseudo-noise code pnt with chip rate Rc = 1/Tc (an integer of Rs) Spreading: In the transmitter, the binary data dt (for BPSK, I and Q for QPSK) is ‘directly multiplied with the PN sequence pnt , which is independent of the binary data, to produce the transmitted baseband signal txb: txb = dt . pnt The effect of multiplication of dt with a PN sequence is to spread the baseband bandwidth Rs of dt to a baseband bandwidth of Rc. Despreading: The spread spectrum signal cannot be detected by a conventional narrowband receiver. In the receiver, the baseband signal rxb is multiplied with the PN sequence pnr . If pnr = pnt and synchronized to the PN sequence in the received data, than the recovered binary data is produced on dr. The effect of multiplication of the spread spectrum signal rxb with the PN sequence pnt used in the transmitter is to despread the bandwidth of rxb to Rs . If pnr ≠  pnt , than there is no dispreading action. The signal dr has a spread spectrum. A receiver not knowing the PN sequence of the transmitter can not reproduce the transmitted data. Performance in the presence of interference: To simplify the presence of interference, the spread spectrum system is considered for baseband BPSK communication (without filtering). The received signal rxb of the transmitted signal txb plus an additive inteferance i (noise, other users, jammer,†¦Ã¢â‚¬ ¦): rxb = t xb + i = dt . pnt + i To recover the original data dt the received signal rx0 is multiplied with a locally generated PN sequence pnr that is an exact replica of that used in the transmitter (that is pnr = pnt and synchronized) The multiplier output is therefore given by: dr = rxb . pnt = dt . pnt . pnt + i . pnt The data signal dt is multiplied twice by the PN sequence pnt , where as the unwanted inteferance i is multiplied only once. Due to the property of the PN sequence: pnt + pnt = +1 for all t The multiplier output becomes: dr = dt + i . pnt The data signal dr is reproduced at the multiplier output in the receiver, except for the inteferance represented by the additive term i . pnt . Multiplication of the inteferance by the locally generated PN sequence, means that the spreading code will affect the inteferance just as it did with the information bearing signal at the transmitter. Noise and inteferance, being uncorrelated with the PN sequence, becomes noise-like, increase in bandwidth and decrease in power density after the multiplier. After dispreading, the data component dt is narrow band (Rb) whereas the inteferance component is wideband (Rc). By applying the dr signal to a baseband (low-pass) filter with a band width just large enough to accommodate the recovery of the data signal, most of the inteferance component i is filtered out. The effect of inteferance is reduced by processing gain (Gp). Narrowband inteferance: The narrowband noise is spread by the multiplication with the PN sequence pnr of the receiver. The power density of the noise is reduced with respect to the despread data signal. Only 1/Gp of the original noise power is left in the information baseband (Rs). Spreading and dispreading enables a bandwidth trade for processing gain against narrow band interfering signals. Narrow band inteferance would disable conventional narrow band receivers. The essence behind the inteferance rejection capability of a spread spectrum system: the useful signal (data) gets multiplied twice by the PN sequence, but the inteferance signal get multiplied only once. Wideband interference: Multiplication of the received signal with the PN sequence of the receiver gets a selective despread of the data signal (smaller bandwidth, higher power density). The inteferance signal is uncorrelated with the PN sequence and is spread. Origin of wideband noise: Multiple Spread Spectrum user: multiple access mechanism. Gaussian Noise: There is no increase in SNR with spread spectrum: The large channel bandwidth (Rc instead of Rs) increase the received noise power with Gp: Ninfo = N0 . BWinfo à   Nss = N0 . BWss = Ninfo .Gp The spread spectrum signal has a lower power density than the directly transmitted signal. Code division multiple access (CDMA) is a methode of multiplexing (wireless) users distinct (orthogonal) codes. All users can transmit at the same time, and each is allocated the entire available frequency spectrum for transmission. CDMA is also known as Spread-Spectrum multiple access (SSMA). CDMA dose not require the bandwidth allocation of FDMA, nor the time synchronization of the individual users needed in TDMA. A CDMA user has full time and full bandwidth available, but the quality of the communication decreases with an increasing number of users (BER ). In CDMA each user: Has its own PN code Uses the same RF bandwidth Transmits simultaneously (asynchronous or synchronous) Correlation of the received baseband spread spectrum signal rxb with the PN sequence of user 1 only despreads the signal of user 1. The other user produces noise Nu for user 1. ACCESS SCHEMES For radio systems there are two resources, frequency and time. Division by frequency, so that each pair of communicators is allocated part of the spectrum for all of the time, results in Frequency Division Multiple Access (FDMA). Division by time, so that each pair of communicators is allocated all (or at least a large part) of the spectrum for part of the time results in Time Division Multiple Access (TDMA). In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time. CDMA uses codes to identify connections. MULTIPATH AND RAKE RECEIVERS One of the main advantages of CDMA systems is the capability of using signals that arrive in the receivers with different time delays. This phenomenon is called multipath. FDMA and TDMA, which are narrow band systems, cannot discriminate between the multipath arrivals, and resort to equalization to mitigate the negative effects of multipath. Due to its wide bandwidth and rake receivers, CDMA uses the multipath signals and combines them to make an even stronger signal at the receivers. CDMA subscriber units use rake receivers. This is essentially a set of several receivers. One of the receivers (fingers) constantly searches for different multipaths and feeds the information to the other three fingers. Each finger then demodulates the signal corresponding to a strong multipath. The results are then combined together to make the signal stronger. Difference between TDMA vs CDMA. TDMA is Time Division Multiple Access, while CDMA is Code Division Multiple Access. Both technologies achieve the same goal of better utilization of the radio spectrum by allowing multiple users to share the same physical channel, but by using different methods and that is why the three of the four words in each acronym are identical. Both allow more than one person to carry out a conversation on the same frequency without causing interference. The two technologies differ in the way in which users share the common resource. In TDMA the channel is chopped up into sequential time slices. The data of each user is put on the channel in a round-robin fashion. In reality, only one user actually uses the channel at any given point of time, but he uses it only for short bursts. He then gives up the channel for a short duration to allow the other users to have their turn. This is similar to how a computer with just one processor runs multiple applications simultaneously. CDMA on the other hand allows everyone to transmit at the same time. With conventional methods of modulation techniques it would hav been simply not possible. What makes CDMA to allow all users to transmit simultaneously is a special type of digital modulation called Spread Spectrum. In this modulation technique users stream of bits is taken and splattered them across a very wide channel in a pseudo-random fashion. The pseudo part is very important here as at the receiver end the randomization must be undone in order to collect the bits together in a coherent order. For example consider a room full of couples, and each couple trying to carry on one-on-one conversations. In TDMA each couple takes their turn for talking and they keep their turns short by speaking only one sentence at a time. As there is always more one person speaking in the room at any given point of time, no one has to worry about being heard over the background din. In CDMA assume each couple talks simultaneously, but they all use different languages. The background din doesnt cause any real problem as none of the listeners understand any language other than that of the individual to whom they are listening. Voice Encoding At this point many people confuse two distinctly different issues involved in the transmission of digital audio. The first is the WAY in which the stream of bits is delivered from one end to the other. This part of the air interface is what makes one technology different from another. The second is the compression algorithm used to squeeze the audio into as small a stream of bits as possible. This latter component is known at the Voice Coder, or Vocoder for short. Another term commonly used is CODEC, which is a similar word to modem. It combines the terms COder and DECoder. Although each technology has chosen their own unique CODECs, there is no rule saying that one transmission method needs to use a specific CODEC. People often lump a technologys transmission method with its CODEC as though they were single entities. Voice encoding schemes differ slightly in their approach to the problem. Because of this, certain types of human voice work better with some CODECs than they do with others. The point to remember is that all PCS CODECs are compromises of some sort. Since human voices have such a fantastic range of pitch and tonal depth, one cannot expect any single compromise to handle each one equally well. This inability to cope with all types of voice at the same level does lead some people to choose one technology over another. All of the PCS technologies try to minimize battery consumption during calls by keeping the transmission of unnecessary data to a minimum. The phone decides whether or not you are presently speaking, or if the sound it hears is just background noise. If the phone determines that there is no intelligent data to transmit it blanks the audio and it reduces the transmitter duty cycle (in the case of TDMA) or the number of transmitted bits (in the case of CDMA). When the audio is blanked your caller would suddenly find themselves listening to dead air, and this may cause them to think the call has dropped. To avoid this psychological problem many service providers insert what is known as Comfort Noise during the blanked periods. Comfort Noise is synthesized white noise that tries to mimic the volume and structure of the real background noise. This fake background noise assures the caller that the connection is alive and well. However, in newer CODECs such as EVRC (used exclusively on CDMA systems) the background noise is generally suppressed even while the user is talking. This piece of magic makes it sound as though the cell phone user is not in a noisy environment at all. Under these conditions, Comfort Noise is neither necessary, nor desirable. DS-CDMA-INTRODUCTION While multiple access interference (MAI) by other users has been recognized as the capacity-limiting factor in direct sequence code-division multiple-access (DS-CDMA)-based cellular communication systems, multiuser approaches have largely alleviated the problem when the noise process is additive Gaussian. With the availability of multiuser detectors, inaccurate or inappropriate noise modelling assumptions seem to have become the issue again. Whereas multiuser detection has much to offer in the mobile- to-base station uplink, it does not at present appear to be feasible for the downlink due to the complexity involved and the lack of resistance against adjacent cell interference. Moreover, the few multiuser proposals for the downlink require the knowledge of all spreading codes, which is not possible in the tactical military environment, for instance. Enhanced single-user receivers equipped with adaptive filter banks deliver promising performance with reasonable complexity, especially in slowly varying channels. Thus, the performance of single-user detectors is still of interest, particularly in the presence of non-Gaussian noise. In both urban outdoor and indoor mobile radio environments, electromagnetic interference generated by man-made sources such as factories or power lines causes the noise to be of non-Gaussian nature. Large noise magnitudes are deemed very improbable by linear receivers, and consequently performance deterioration is experienced. It is therefore desirable to build systems that can maintain respectable functionality under a broad class of noise distributions, rather than strictly optimizing for the unrealistic Gaussian assumption. Such is the goal of robust detection and estimation theory, which aims to design systems that are suboptimal under nominal channel conditions (e.g., Gaussian channel) and yet do not face catastrophy when the noise distribution is not nominal (e.g., unlike linear schemes). Note that suboptimality here refers to very good performance that is slightly worse than that of the nominal-optimal detector/estimator. The direct sequence code division multiple access (DS-CDMA) technique has been favourably considered for application in digital mobile cellular networks due to its potential to provide higher system capacity over conventional multiple access techniques. Unlike FDMA and TDMA capacities which are mostly limited by the bandwidth, the capacity of a CDMA system is mainly restricted by its interference level. Any reduction in interference produces a direct and linear increase in system capacity. Multiple access interference (MAI) caused by non-zero cross-correlation between different spreading sequences is the major type of interference limiting the CDMA system capacity. Much work has been done to characterize MAI, and to analyze and evaluate the CDMA system performance in the presence of MAI. Since the cross-correlation properties of most sets of spreading codes are either too complex to analyze or very difficult to compute when different transmissions are not synchronized, a random seque nce model. In the case of moderate to large processing gains, Gaussian distribution with variable variance is a good approximation for the MAI distribution. One of the approaches to reduce MAI is to employ orthogonal spreading sequences, and try to synchronize the transmissions at the chip level (quasi-synchronization). However, this is generally difficult to achieve in multipoint-to-point systems, such as the reverse link (mobile-to-base) of a cellular system, due to a lack of synchronization of the various mobile terminals, and the variable transmission delays. In this paper, a multi-carrier DS-CDMA (MCDS-CDMA) scheme is employed to facilitate the synchronization process, and thus reduce MAI. SYSTEM MODEL A model of the MS-DS-CDMA system for the kth user of a CDMA system is shown in the figure 1. TRANMSITTER MODEL At the transmitter the user‘s data stream dk(t) is divided into M interleaved sub streams and spread by a spreading sequence ck(t) to a fraction 1/M of the entire transmission bandwidth W. The resultant chip sequences are then used to modulate M carrier. The carrier frequencies ωm,m=1,2,M are equally spaced by the chip rate so that they are mutually orthogonal over one channel symbol interval T. Let R be the information rate and Rc be the carrier control code rate then the channel symbol interval is BER PERFORMANCE: MC-DS-CDMA system performance measured by bit error rate through analysis and simulation. Analysis: The BER is analysed based on the following: Ortoganal spreading sequences with rectangular pulse shape are applied. ÃŽ ¶k,k=1†¦K are independent of random variables distributd in (-ÃŽ ¶D,ÃŽ ¶D) WHERE ÃŽ ¶D=ÃŽ µD+Ï‚D.Given W and ÃŽ ¶D,M is chosen so that ÃŽ ¶D It is assumed that the fading parameters of the desired user . It is perfectly estimated so that the coherent detection and optimum soft decision decoding could be carried out at the receiver to make the problem analytically tractable. The fading amplitudes as independent Rayleigh random variables with equal second moments. The model is MATLAB INTRODUCTION: Matlab is a commercial Matrix Laboratory package which operates as an interactive programming environment. It is a mainstay of the Mathematics Department software lineup and is also available for PCs and Macintoshes and may be found on the CIRCA VAXes. Matlab is well adapted to numerical experiments since the underlying algorithms for Matlabs builtin functions and supplied m-files are based on the standard libraries LINPACK and EISPACK. Matlab program and script files always have filenames ending with .m; the programming language is exceptionally straightforward since almost every data object is assumed to be an array. Graphical output is available to supplement numerical results. IMREAD Read image from graphics file. A = IMREAD(FILENAME,FMT) reads a grayscale or color image from the file specified by the string FILENAME. If the file is not in the current directory, or in a directory on the MATLAB path, specify the full pathname. The text string FMT specifies the format of the file by its standard file extension. For example, specify gif Digital Signal Processing (DSP) and CDMA Advantages Digital Signal Processing (DSP) and CDMA Advantages INTRODUCTION ANALOG AND DIGITAL SIGNALS The signal is initially generated is in the form of an analog electrical voltage or current, produced for example by a microphone or some other type of transducer. The output from the readout system of a CD (compact disc) player, the data is already in digital form. An analog signal must be converted into digital form before DSP techniques can be applied. An analog electrical voltage signal, for example, can be digitized using an electronic circuit called an analog-to-digital converter or ADC. This generates a digital output as a stream of binary numbers whose values represent the electrical voltage input to the device at each sampling instant. Digital signal processing (DSP)-digital representation of signals and the use of digital processors to analyze, modify, or extract information from signals. Many signals in DSP are derived from analogue signals which have been sampled at regular intervals and converted into digital form. The key advantages of DSP over analogue processing are Guaranteed accuracy (determined by the number of bits used) Perfect reproducibility No drift in performance due to temperature or age Takes advantage of advances in semiconductor technology Greater flexibility (can be reprogrammed without modifying hardware) Superior performance (linear phase response possible, and filtering algorithms can be made adaptive) Sometimes information may already be in digital form. There are however (still) some disadvantages Speed and cost (DSP design and hardware may be expensive, especially with high bandwidth signals) Finite word length problems (limited number of bits may cause degradation). Application areas of DSP are considerable: Image processing (pattern recognition, robotic vision, image enhancement, facsimile, satellite weather map, animation) Instrumentation and control (spectrum analysis, position and rate control, noise reduction, data compression) Speech and audio (speech recognition, speech synthesis, text to speech, digital audio, equalisation) Military (secure communication, radar processing, sonar processing, missile guidance) Telecommunications (echo cancellation, adaptive equalisation, spread spectrum, video conferencing, data communication) Biomedical (patient monitoring, scanners, EEG brain mappers, ECG analysis, X-ray storage and enhancement). INTRODUCTION TO CDMA Code Division Multiple Access (CDMA) is a radically new concept in wireless communications. It has gained widespread international acceptance by cellular radio system operators as an upgrade that will dramatically increase both their system capacity and the service quality. It has likewise been chosen for deployment by the majority of the winners of the United States Personal Communications System spectrum auctions. It may seem, however, mysterious for those who arent familiar with it. CDMA is a form of spread-spectrum, a family of digital communication techniques that have been used in military applications for many years. The core principle of spread spectrum is the use of noise-like carrier waves, and, as the name implies, bandwidths much wider than that required for simple point-to-point communication at the same data rate. Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called low probability of intercept (LPI). It has a history that goes back to the early days of World War II. The use of CDMA for civilian mobile radio applications is novel. It was proposed theoretically in the late 1940s, but the practical application in the civilian marketplace did not take place until 40 years later. Commercial applications became possible because of two evolutionary developments. One was the availability of very low cost, high density digital integrated circuits, which reduce the size, weight, and cost of the subscriber stations to an acceptably low level. The other was the realization that optimal multiple access communication requires that all user stations regulate their transmitter powers to the lowest that will achieve adequate signal quality. CDMA changes the nature of the subscriber station from a predominately analog device to a predominately digital device. Old-fashioned radio receivers separate stations or channels by filtering in the frequency domain. CDMA receivers do not eliminate analog processing entirely, but they separate communication channels by means of a pseudorandom modulation that is applied and removed in the digital domain, not on the basis of frequency. Multiple users occupy the same frequency band. This universal frequency reuse is not fortuitous. On the contrary, it is crucial to the very high spectral efficiency that is the hallmark of CDMA. Other discussions in these pages show why this is true. CDMA is altering the face of cellular and PCS communication by: Dramatically improving the telephone traffic capacity Dramatically improving the voice quality and eliminating the audible effects of multipath fading Reducing the incidence of dropped calls due to handoff failures Providing reliable transport mechanism for data communications, such as facsimile and internet traffic Reducing the number of sites needed to support any given amount of traffic Simplifying site selection Reducing deployment and operating costs because fewer cell sites are needed Reducing average transmitted power Reducing interference to other electronic devices Reducing potential health risks Commercially introduced in 1995, CDMA quickly became one of the worlds fastest growing wireless technologies. In 1999, the International Telecommunications Union selected CDMA as the industry standard for new third-generation (3G) wireless systems. Many leading wireless carriers are now building or upgrading to 3G CDMA networks in order to provide more capacity for voice traffic, along with high-speed data capabilities. DS_CDMA Multiple access systems based on DS CDMA have achieved increasing significance for mobile communications applications. A promising concept is based on DS_CDMA applying MRC at the receiver. MRC takes advantage of the channel diversity to combat the multipath fading. However the capacity of a DS_CDMA system is limited by both multi-user interference and inter symbol interference ISI in high data rate applications. OFDM is applied to combat the frequency selectivity of the channel using a simple one tap equalizer Further more OFDM prevents the ISI and inter carrier interference ICI by inserting a guard interval between adjacent OFDM symbols OFDM is typically used for audio TV and HDTV transmission over terrestrial channels and achieves high spectral efficiency. The CMDA Technology overview FDMA In Frequency Division Multiple Access, the frequency band is divided in slots. Each user gets one frequency slot assigned that is used at will. It could be compared to AM or FM broadcasting radio where each station has a frequency assigned. FDMA demands good filtering. TDMA In Time Division Multiple Access, the frequency band is not partitioned but users are allowed to use it only in predefined intervals of time, one at a time. Thus, TDMA demands synchronization among the users. CDMA CDMA, for Code Division Multiple Access, is different from its traditional ways in which it does not allocate frequency or time in user slots but gives the right to use both to all users simultaneously. To do this, it uses a technique known as Spread Spectrum . In effect, each user is assigned a code,which spreads its signal bandwidth in such a way that only the same code can recover it at the receiver end. This method has the property that the unwanted signals with different codes get spread even more by the process, making them like noise to the receiver . Spread Spectrum Spread Spectrum is a mean of transmission where the data occupies a larger bandwidth than necessary. Bandwidth spreading is accomplished before the transmission through the use of a code, which is independent of the transmitted data. The same code is used to demodulate the data at the receiving end. The following figure illustrate the spreading done on the data signal x(t) by the spreading signal c(t) resulting in the message signal to be transmitted, m(t). Originally for military use to avoid jamming (interference created on purpose to make a communication channel unusable), spread spectrum modulation is now used in personal communication systems for its superior performance in an interference dominated environment . Definition of Spread Spectrum: A transmission technique in which a pseudo-noise code, independent of the information data, is employed as a modulation waveform to â€Å"spread† the signal energy over a bandwidth much greater than the signal information bandwidth. At the receiver the signal is â€Å"despread† using a synchronized replica of the pseudo-noise code. Basic Principle of Spread Spectrum System: The Principal types of Spread Spectrum are Direct Sequence (DS), and Frequency Hopping (FH). An over view of these systems is hereby given: Pseudo shift of the phase pseudo shift of the frequency Coherent demodulation noncoherent Direct Sequence Spread Spectrum (DSSS) A pseudo-noise sequence pnt generated at the modulator, is used in conjunction with an M-ary PSK modulation to shift the phase of the PSK signal pseudo randomly, at the chipping rate Rc (=1/Tc) a rate that is integer multiple of the symbol rate Rs (=1/Ts). The transmitted bandwidth is determined by the chip rate and by the base band filtering. The implementation limits the maximum chip rate Rc (clock rate) and thus the maximum spreading. The PSK modulation scheme requires a coherent demodulation. PN code length that is much longer than a data symbol, so that a different chip pattern is associated with each symbol. Frequency Hopping Spread Spectrum A Pseudo-noise sequence pnt generated at the modulator is used in conjuction with an M-ary FSK modulation to shift the carrier frequency of the FSK signal pseudurandomly, at the hopping rate Rh. The transmitted signal occupies a number of frequencies in time, each for a period of time Th (= 1/Rh), referred as dwell time. FHSS divides the available bandwidth into N channels and hops between these channels according to the PN sequence. At each frequency hop time the PN generator feeds the frequency synthesizer a frequency word FW (a sequence of n chips) which dictates one of 2n frequency position fhl . Transmitter and receiver follows the same frequency hop pattern. The transmitted bandwidth is determined by the lowest and highest hop position by the bandwidth per hop position (à ¢Ã‹â€ Ã¢â‚¬  fch). For a given hop, instantaneous occupied bandwidth is the conventional M-FSK, which is typically much smaller than Wss. So the FHSS signal is a narrowband signal, all transmission power is concentrated on one channel. Averaged over many hops, the FH/M-FSK spectrum occupies the entire spread spectrum bandwidth. Because the bandwidth of an FHSS system only depends on the tuning range, it can be hopped over a much wider bandwidth than an DSSS system. Since the hops generally result in phase discontinuity (depending on the particular implementation) a noncoherent demodulation is done at receiver. With slow hopping there are multiple data symbol per hop and with fast hopping there are multiple hops per data symbol. 3.3 Basic principle of Direct Sequence Spread Spectrum For BPSK modulation the building blocks of a DSSS system are: Input: Binary data dt with symbol rate Rs = 1/Ts (=bitrate Rb for BPSK) Pseudo-noise code pnt with chip rate Rc = 1/Tc (an integer of Rs) Spreading: In the transmitter, the binary data dt (for BPSK, I and Q for QPSK) is ‘directly multiplied with the PN sequence pnt , which is independent of the binary data, to produce the transmitted baseband signal txb: txb = dt . pnt The effect of multiplication of dt with a PN sequence is to spread the baseband bandwidth Rs of dt to a baseband bandwidth of Rc. Despreading: The spread spectrum signal cannot be detected by a conventional narrowband receiver. In the receiver, the baseband signal rxb is multiplied with the PN sequence pnr . If pnr = pnt and synchronized to the PN sequence in the received data, than the recovered binary data is produced on dr. The effect of multiplication of the spread spectrum signal rxb with the PN sequence pnt used in the transmitter is to despread the bandwidth of rxb to Rs . If pnr ≠  pnt , than there is no dispreading action. The signal dr has a spread spectrum. A receiver not knowing the PN sequence of the transmitter can not reproduce the transmitted data. Performance in the presence of interference: To simplify the presence of interference, the spread spectrum system is considered for baseband BPSK communication (without filtering). The received signal rxb of the transmitted signal txb plus an additive inteferance i (noise, other users, jammer,†¦Ã¢â‚¬ ¦): rxb = t xb + i = dt . pnt + i To recover the original data dt the received signal rx0 is multiplied with a locally generated PN sequence pnr that is an exact replica of that used in the transmitter (that is pnr = pnt and synchronized) The multiplier output is therefore given by: dr = rxb . pnt = dt . pnt . pnt + i . pnt The data signal dt is multiplied twice by the PN sequence pnt , where as the unwanted inteferance i is multiplied only once. Due to the property of the PN sequence: pnt + pnt = +1 for all t The multiplier output becomes: dr = dt + i . pnt The data signal dr is reproduced at the multiplier output in the receiver, except for the inteferance represented by the additive term i . pnt . Multiplication of the inteferance by the locally generated PN sequence, means that the spreading code will affect the inteferance just as it did with the information bearing signal at the transmitter. Noise and inteferance, being uncorrelated with the PN sequence, becomes noise-like, increase in bandwidth and decrease in power density after the multiplier. After dispreading, the data component dt is narrow band (Rb) whereas the inteferance component is wideband (Rc). By applying the dr signal to a baseband (low-pass) filter with a band width just large enough to accommodate the recovery of the data signal, most of the inteferance component i is filtered out. The effect of inteferance is reduced by processing gain (Gp). Narrowband inteferance: The narrowband noise is spread by the multiplication with the PN sequence pnr of the receiver. The power density of the noise is reduced with respect to the despread data signal. Only 1/Gp of the original noise power is left in the information baseband (Rs). Spreading and dispreading enables a bandwidth trade for processing gain against narrow band interfering signals. Narrow band inteferance would disable conventional narrow band receivers. The essence behind the inteferance rejection capability of a spread spectrum system: the useful signal (data) gets multiplied twice by the PN sequence, but the inteferance signal get multiplied only once. Wideband interference: Multiplication of the received signal with the PN sequence of the receiver gets a selective despread of the data signal (smaller bandwidth, higher power density). The inteferance signal is uncorrelated with the PN sequence and is spread. Origin of wideband noise: Multiple Spread Spectrum user: multiple access mechanism. Gaussian Noise: There is no increase in SNR with spread spectrum: The large channel bandwidth (Rc instead of Rs) increase the received noise power with Gp: Ninfo = N0 . BWinfo à   Nss = N0 . BWss = Ninfo .Gp The spread spectrum signal has a lower power density than the directly transmitted signal. Code division multiple access (CDMA) is a methode of multiplexing (wireless) users distinct (orthogonal) codes. All users can transmit at the same time, and each is allocated the entire available frequency spectrum for transmission. CDMA is also known as Spread-Spectrum multiple access (SSMA). CDMA dose not require the bandwidth allocation of FDMA, nor the time synchronization of the individual users needed in TDMA. A CDMA user has full time and full bandwidth available, but the quality of the communication decreases with an increasing number of users (BER ). In CDMA each user: Has its own PN code Uses the same RF bandwidth Transmits simultaneously (asynchronous or synchronous) Correlation of the received baseband spread spectrum signal rxb with the PN sequence of user 1 only despreads the signal of user 1. The other user produces noise Nu for user 1. ACCESS SCHEMES For radio systems there are two resources, frequency and time. Division by frequency, so that each pair of communicators is allocated part of the spectrum for all of the time, results in Frequency Division Multiple Access (FDMA). Division by time, so that each pair of communicators is allocated all (or at least a large part) of the spectrum for part of the time results in Time Division Multiple Access (TDMA). In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time. CDMA uses codes to identify connections. MULTIPATH AND RAKE RECEIVERS One of the main advantages of CDMA systems is the capability of using signals that arrive in the receivers with different time delays. This phenomenon is called multipath. FDMA and TDMA, which are narrow band systems, cannot discriminate between the multipath arrivals, and resort to equalization to mitigate the negative effects of multipath. Due to its wide bandwidth and rake receivers, CDMA uses the multipath signals and combines them to make an even stronger signal at the receivers. CDMA subscriber units use rake receivers. This is essentially a set of several receivers. One of the receivers (fingers) constantly searches for different multipaths and feeds the information to the other three fingers. Each finger then demodulates the signal corresponding to a strong multipath. The results are then combined together to make the signal stronger. Difference between TDMA vs CDMA. TDMA is Time Division Multiple Access, while CDMA is Code Division Multiple Access. Both technologies achieve the same goal of better utilization of the radio spectrum by allowing multiple users to share the same physical channel, but by using different methods and that is why the three of the four words in each acronym are identical. Both allow more than one person to carry out a conversation on the same frequency without causing interference. The two technologies differ in the way in which users share the common resource. In TDMA the channel is chopped up into sequential time slices. The data of each user is put on the channel in a round-robin fashion. In reality, only one user actually uses the channel at any given point of time, but he uses it only for short bursts. He then gives up the channel for a short duration to allow the other users to have their turn. This is similar to how a computer with just one processor runs multiple applications simultaneously. CDMA on the other hand allows everyone to transmit at the same time. With conventional methods of modulation techniques it would hav been simply not possible. What makes CDMA to allow all users to transmit simultaneously is a special type of digital modulation called Spread Spectrum. In this modulation technique users stream of bits is taken and splattered them across a very wide channel in a pseudo-random fashion. The pseudo part is very important here as at the receiver end the randomization must be undone in order to collect the bits together in a coherent order. For example consider a room full of couples, and each couple trying to carry on one-on-one conversations. In TDMA each couple takes their turn for talking and they keep their turns short by speaking only one sentence at a time. As there is always more one person speaking in the room at any given point of time, no one has to worry about being heard over the background din. In CDMA assume each couple talks simultaneously, but they all use different languages. The background din doesnt cause any real problem as none of the listeners understand any language other than that of the individual to whom they are listening. Voice Encoding At this point many people confuse two distinctly different issues involved in the transmission of digital audio. The first is the WAY in which the stream of bits is delivered from one end to the other. This part of the air interface is what makes one technology different from another. The second is the compression algorithm used to squeeze the audio into as small a stream of bits as possible. This latter component is known at the Voice Coder, or Vocoder for short. Another term commonly used is CODEC, which is a similar word to modem. It combines the terms COder and DECoder. Although each technology has chosen their own unique CODECs, there is no rule saying that one transmission method needs to use a specific CODEC. People often lump a technologys transmission method with its CODEC as though they were single entities. Voice encoding schemes differ slightly in their approach to the problem. Because of this, certain types of human voice work better with some CODECs than they do with others. The point to remember is that all PCS CODECs are compromises of some sort. Since human voices have such a fantastic range of pitch and tonal depth, one cannot expect any single compromise to handle each one equally well. This inability to cope with all types of voice at the same level does lead some people to choose one technology over another. All of the PCS technologies try to minimize battery consumption during calls by keeping the transmission of unnecessary data to a minimum. The phone decides whether or not you are presently speaking, or if the sound it hears is just background noise. If the phone determines that there is no intelligent data to transmit it blanks the audio and it reduces the transmitter duty cycle (in the case of TDMA) or the number of transmitted bits (in the case of CDMA). When the audio is blanked your caller would suddenly find themselves listening to dead air, and this may cause them to think the call has dropped. To avoid this psychological problem many service providers insert what is known as Comfort Noise during the blanked periods. Comfort Noise is synthesized white noise that tries to mimic the volume and structure of the real background noise. This fake background noise assures the caller that the connection is alive and well. However, in newer CODECs such as EVRC (used exclusively on CDMA systems) the background noise is generally suppressed even while the user is talking. This piece of magic makes it sound as though the cell phone user is not in a noisy environment at all. Under these conditions, Comfort Noise is neither necessary, nor desirable. DS-CDMA-INTRODUCTION While multiple access interference (MAI) by other users has been recognized as the capacity-limiting factor in direct sequence code-division multiple-access (DS-CDMA)-based cellular communication systems, multiuser approaches have largely alleviated the problem when the noise process is additive Gaussian. With the availability of multiuser detectors, inaccurate or inappropriate noise modelling assumptions seem to have become the issue again. Whereas multiuser detection has much to offer in the mobile- to-base station uplink, it does not at present appear to be feasible for the downlink due to the complexity involved and the lack of resistance against adjacent cell interference. Moreover, the few multiuser proposals for the downlink require the knowledge of all spreading codes, which is not possible in the tactical military environment, for instance. Enhanced single-user receivers equipped with adaptive filter banks deliver promising performance with reasonable complexity, especially in slowly varying channels. Thus, the performance of single-user detectors is still of interest, particularly in the presence of non-Gaussian noise. In both urban outdoor and indoor mobile radio environments, electromagnetic interference generated by man-made sources such as factories or power lines causes the noise to be of non-Gaussian nature. Large noise magnitudes are deemed very improbable by linear receivers, and consequently performance deterioration is experienced. It is therefore desirable to build systems that can maintain respectable functionality under a broad class of noise distributions, rather than strictly optimizing for the unrealistic Gaussian assumption. Such is the goal of robust detection and estimation theory, which aims to design systems that are suboptimal under nominal channel conditions (e.g., Gaussian channel) and yet do not face catastrophy when the noise distribution is not nominal (e.g., unlike linear schemes). Note that suboptimality here refers to very good performance that is slightly worse than that of the nominal-optimal detector/estimator. The direct sequence code division multiple access (DS-CDMA) technique has been favourably considered for application in digital mobile cellular networks due to its potential to provide higher system capacity over conventional multiple access techniques. Unlike FDMA and TDMA capacities which are mostly limited by the bandwidth, the capacity of a CDMA system is mainly restricted by its interference level. Any reduction in interference produces a direct and linear increase in system capacity. Multiple access interference (MAI) caused by non-zero cross-correlation between different spreading sequences is the major type of interference limiting the CDMA system capacity. Much work has been done to characterize MAI, and to analyze and evaluate the CDMA system performance in the presence of MAI. Since the cross-correlation properties of most sets of spreading codes are either too complex to analyze or very difficult to compute when different transmissions are not synchronized, a random seque nce model. In the case of moderate to large processing gains, Gaussian distribution with variable variance is a good approximation for the MAI distribution. One of the approaches to reduce MAI is to employ orthogonal spreading sequences, and try to synchronize the transmissions at the chip level (quasi-synchronization). However, this is generally difficult to achieve in multipoint-to-point systems, such as the reverse link (mobile-to-base) of a cellular system, due to a lack of synchronization of the various mobile terminals, and the variable transmission delays. In this paper, a multi-carrier DS-CDMA (MCDS-CDMA) scheme is employed to facilitate the synchronization process, and thus reduce MAI. SYSTEM MODEL A model of the MS-DS-CDMA system for the kth user of a CDMA system is shown in the figure 1. TRANMSITTER MODEL At the transmitter the user‘s data stream dk(t) is divided into M interleaved sub streams and spread by a spreading sequence ck(t) to a fraction 1/M of the entire transmission bandwidth W. The resultant chip sequences are then used to modulate M carrier. The carrier frequencies ωm,m=1,2,M are equally spaced by the chip rate so that they are mutually orthogonal over one channel symbol interval T. Let R be the information rate and Rc be the carrier control code rate then the channel symbol interval is BER PERFORMANCE: MC-DS-CDMA system performance measured by bit error rate through analysis and simulation. Analysis: The BER is analysed based on the following: Ortoganal spreading sequences with rectangular pulse shape are applied. ÃŽ ¶k,k=1†¦K are independent of random variables distributd in (-ÃŽ ¶D,ÃŽ ¶D) WHERE ÃŽ ¶D=ÃŽ µD+Ï‚D.Given W and ÃŽ ¶D,M is chosen so that ÃŽ ¶D It is assumed that the fading parameters of the desired user . It is perfectly estimated so that the coherent detection and optimum soft decision decoding could be carried out at the receiver to make the problem analytically tractable. The fading amplitudes as independent Rayleigh random variables with equal second moments. The model is MATLAB INTRODUCTION: Matlab is a commercial Matrix Laboratory package which operates as an interactive programming environment. It is a mainstay of the Mathematics Department software lineup and is also available for PCs and Macintoshes and may be found on the CIRCA VAXes. Matlab is well adapted to numerical experiments since the underlying algorithms for Matlabs builtin functions and supplied m-files are based on the standard libraries LINPACK and EISPACK. Matlab program and script files always have filenames ending with .m; the programming language is exceptionally straightforward since almost every data object is assumed to be an array. Graphical output is available to supplement numerical results. IMREAD Read image from graphics file. A = IMREAD(FILENAME,FMT) reads a grayscale or color image from the file specified by the string FILENAME. If the file is not in the current directory, or in a directory on the MATLAB path, specify the full pathname. The text string FMT specifies the format of the file by its standard file extension. For example, specify gif

The Yellow Wallpaper and The Cask Of Amontillado -- Yellow Wallpaper C

The Yellow Wallpaper and The Cask Of Amontillado  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚      The short story, " The Yellow Wallpaper", written by Charlotte Gilman, and "The Cask of Amontillado" written by Edgar Allan Poe, are stories in which the plots are very different, but share similar qualities with the elements in the story. "The Cask of Amontillado" is a powerful tale of revenge, in which the narrator of the tale pledges revenge upon Fortunato for an insult. "The Yellow Wallpaper" is a story about a woman, her psychological difficulties and her husband's therapeutic treatment of her illness. She struggles over her illness, and battle's her controlling husband. The settings in both stories are very important, they influence the characters, and help with the development of the plot.   In "The Yellow Wallpaper" the setting helps define the action as well as to explain characters behaviors. The setting is which the story takes place is in the narrators room, where she is severally ill, and she is "locked up" in the room which served as her cage. The room in which the narrator is caged in is a nursery, "it is a big, airy room, the whole floor nearly, with windows that look all ways. The paint and paper look as if a boys' school had used it." The narrator describes the color of the walls as repellent, almost revolting, it is an unclear yellow with a dull orange. The condition that the narrator is in, the repulsiveness of the room, and the room haunting her, drives her into insanity.   "The Cask of Amontillado" takes place in an appropriate setting, not only is the setting underground, but also in the blackness of the night. The story begins around dusk, one evening during the carnival season in a European city. The location quickly change... ...he wall, he thinks about his rejected opportunities and his unbearable regret. As he sobers with terror, the final blow will come from the realization that his life is ending in his catacombs dying with his finest wine. The catacombs, in which he dies, set the theme, and relate well with the story. Without the yellow wallpaper in the short story, the significance of the wallpaper would not mater, nor would it set the theme or plot. At night the wallpaper becomes bars, and the wallpaper lets her see herself as a women and her desire to free herself. She needs to free herself from the difficulties of her husband, and from her sickness. The settings in both, set up the elements of the stories and ads to the effect in both of the short stories.   Bibliography Branson, Leigh W. Edgar Allen Poe's Literary Neighborhood, 17 Mar. 1997 *htt://www.geocities.com/Athens

Hearts and Minds Essay

Movies and documentaries have a way of touching the lives of many. For the most part, they are geared towards the exhibition of truths that are hidden from other people. The documentary, â€Å"Hearts and Minds†, mirrored the numerous difficulties experienced by the Vietnamese in the hands of the American soldiers. The harsh realities shown by the American soldiers towards the Vietnamese was quite difficult to believe, for we all know how the Americans would care for any other individual. Directed by Peter Davis, the documentary showed different clips that prove the harsh attitude towards people at that time. Even the speech of former President Lyndon Johnson was shown in the said documentary. To give people a great feel of the said timeline, much of the most famous details during that particular time were shown. The type of music, clothes, and even some old archives were shown. In this manner, it would become easier for the audiences to understand what was being explained to them. I admire the montage feeling provided by the documentary. Together with the voice over, watching the documentary was like watching any other historical how. However, what sets it apart from the rest were the heartbreaking realities exhibited. I could not help but wonder as to how people were treated unfairly and how other people could bear causing pain to others. One of the scenes that caught my attention was the funeral of a soldier. Surrounding the coffin were grieving people, including the family and friends. However, for some reason, one grieving lady was stopped from following the coffin being laid to rest. This particular scene was contrasted with a clip showing the interview of the general who led the Vietnam War. Furthermore, there were several other interviews included in the documentary. Although I am not of Vietnamese, origin I was heartbroken by the difficulties experienced at that time. For the longest time, they experienced pain, both physical and emotional, while they struggled to raise their families accordingly. A particular scene exemplified the hardships endured by the Vietnamese during that particular time. The scene showed how the prisoners of the war were sitting restless and not paying attention to what their employer had in mind. I felt pity with the condition these people experienced, toppled by the excessive torture and inhumane humiliations provided by the American soldiers. After watching the documentary, one could not help but question what has been taught in class during our younger days. I was surprised at how the outcome of this war has been, including the participation that the American soldiers portrayed. However, due to the extensive information provided, some critics may also form their own conclusion as to how the said war was used as propaganda. On the other hand, it would be expected that some people would opt to be biased towards the Vietnamese and consider them to be victims of the American occupation. Regardless of everything that has been said, I believe that we all have our own perceptions towards things. Personally, I believe that the goal of this film was to show the other side of history that not everyone was aware of. In this manner, I would be able to form my own beliefs as to how people would be able to learn from these hurtful experiences. It is useless for us to keep on living in the past—we should all move forward in helping make a different in this lifetime. I must say that I recommend this film to everyone, especially those who are currently studying about the history of the United States.

Words Often Misspelled Because of Double Letters

Words Often Misspelled Because of Double Letters Words Often Misspelled Because of Double Letters Words Often Misspelled Because of Double Letters By Maeve Maddox An email in which balloon was spelled â€Å"baloon† got me thinking about words with double letters. Many of the most frequently-misspelled words in English are misspelled by leaving out a letter. Others are misspelled because we think a letter should be doubled, so we put in an extra one. I thought it might be useful to organize these frequently-misspelled words into three categories. Words we try to spell with too few letters balloon dumbbell embarrass millennium misspell occurrence possession broccoli occasionally questionnaire coolly dissipate difference generally incidentally magically success Words that have double letters, but not as many as we think deterrence harass personnel recommend referred disappear disappoint finally fulfill necessary occasion occurred parallel sheriff tomorrow Words that don’t have double letters, but we want to add them preferable procedure coliseum labeled NOTE: i. There’s also the spelling colosseum with a double s. ii. British usage doubles the l in labelled. Caveat to writers of British English: Most word-processing software comes with spell-checkers programmed for American spelling usage. Another NOTE: Merriam-Webster gives programmed as the first spelling and programed as an alternate. Go figure. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Spelling category, check our popular posts, or choose a related post below:Spelling Test 18 Types of Parenthetical PhrasesWriting a Thank You Note

Cultural Literacy Example

Cultural Literacy Example Cultural Literacy – Coursework Example Cultural Literacy Key differences between American and Chinese culture originate in the differences in people’s lifestyles, socializing habits, and cuisines and eating habits etcetera. While Americans are more independently going, self-oriented, and have well-defined personal space, Chinese are more community-oriented with strong family ties and robust social network. If I were to do business in China, I would have to be more open and vivacious in greeting others. I would be expected to have a lot of friends and Chinese people are not difficult to make friends as they are quite friendly and easy going. Once upon a time, I was in a gathering. There were my American neighbors and a couple from the Middle East. Handshaking between men and women is a common practice in the US. People shake hands all the time, whether they are in office, park, or at home with friends. My American neighbor John, who also happens to be my close friend, was the host. While we were attending the guests , John offered the Middle Eastern couple some wine, but they respectfully refused. I could sense that John did not like that since he had spent a lot on wine. This was where I intruded and said with a wide grin on my face,†haha; America is a melting pot of cultures, beautifully blending yet retaining their originality; right John?† John got the point and joined in the conversation. What could otherwise have been jeopardized in a misunderstanding, sprang into a strong networking with good understanding of and respect for the cultural differences as a result of my intervention.

Term paper Example | Topics and Well Written Essays - 1500 words

Term Paper Example It is further concerned with other activities such as the disposition of offenders and treatment of juveniles found to have committed a criminal act. The criminal justice system also includes public institutions and key players such as the police, prosecutors, courts, corrections, crime victims and so on (â€Å"Criminal Justice System†). Purpose According to Frase and Weidner, the criminal justice system has the primary purpose of enforcing laws in line with the defined rules and limitations. The authors furthered that the â€Å"system† refers to â€Å"something highly rational – carefully planned, coordinated, and regulated† (Frase & Weidner). On the other hand, Drakeford and Friedman reiterated that controlling crime and assuring due process are the two main purposes of the criminal justice system (5). Key Players’ Functions The criminal justice system is composed of four institutions, namely, police, prosecution, courts, and corrections, and thes e interact with each other towards a balanced action for justice. In simpler terms, the police are responsible for enforcing the law; the courts are responsible for hearing the legality of the crime, and; corrections house the convicted offenders. The following section lists the specific responsibilities of these key players. Police. According to Stevens, the police have intended and unintended functions that include the following: morals enforcement, class control, riot control, order maintenance, safety, service, and crime fighting. Other specific functions include the following: To subdue conduct that is considered threatening. To protect or help a person who is harmed. To uphold security in the community. To help people who are unable to help themselves such as the handicap, the mentally ill, the old and the young, and others. To help in resolving conflict between groups and individuals. To oversee the movement of vehicles and people. To recognize problems that can become seriou s problems (Stevens). Prosecutor. The main function of the prosecutor in a trial is to convince the jury that the defendant is guilty of the crime. Other functions include, but not limited to, the following: To ensure that the guilty person is convicted. To charge suspect with a crime. To represent the government during a trial. To assist in selecting jurors. To call on witnesses to prove the defendant’s guilt. To cross-examine the witnesses presented by the defense (Read). Court. The court consists of the prosecutors, judges and other stakeholders, each of which has roles to fulfill. The prosecuting office must present evidence to the court regarding the guilt of the offender. The prosecutor is usually involved during the initial investigation, pretrial hearings and during the trial. During the preliminary hearing, several factors such as the severity of the offense, will determine the next step. The lack of probable cause can lead to the dismissal of the case. Otherwise the case may be brought to the grand jury. If there is sufficient evidence, the grand jury then decides to try the offender (Drakeford & Friedman, 8-9). Corrections. Drakeford and Friedman stated that corrections have several purposes, one of which is to punish the offenders. This is based on the belief that punishment deters offenders from criminal behavior. Another purpose of the corrections is to protect the society from these offenders. The third purpose is to rehabilitate the offenders (10). Interaction of Key Players The key players in the criminal justice system,